The invention relates to a stereoscopic image capture system. Such a system commonly comprises a device described as a 3D camera, or stereoscopic camera.
The invention particularly considers a stereoscopic image capture system that provides depth information, or equivalent information. The cameras of these systems are described as depth sensors, or depth cameras. These sensors make it possible to obtain images captured from two points of view, which, after processing, make it possible to obtain depth information, or any equivalent information, generally described as disparity information. It is obtained point by point (pixel by pixel) in the image, and referred to as a depth map.
The invention in particular relates to a stereoscopic image capture system for capturing images while moving, at low or high speed, within an environment made up of stationary or static objects that are opposite the device for capturing images of the relative movements.
Depth cameras are known based on the measurement of a time of flight of a light wave emitted by illumination means such as LEDs, and reflected the encountered objects. The wave may be an infrared wave. The time of flight, measured pixel by pixel, makes it possible to determine the distance of the reflective surface from the transmitting device. Time of flight cameras have the flaw of being sensitive to disruptions, such as infrared waves emitted by the environment, in particular the sun, or interference, in particular coming from other time of flight cameras, for example encountered during the movement of the vehicle with the camera on board and that passes other vehicles with similar cameras on board.
LIDAR (light detection and ranging) systems, or laser radars, are also known reading (scanning) the environment with a generally coherent light, emitted by scanning using a heavy mechanical system that must be very precise. The system is cumbersome, and requires regular maintenance, due to the mechanical scanner system. It is more expensive for these two reasons. It is also blinded in case of rain and fog by the reflection caused by the cloudiness.
Also known is document US 20070296846, which discloses a stereoscopic camera comprising two digital image sensors placed at a distance from one another by a chassis. The positioning of the sensors is obtained by a precise mechanical engagement between the parts. Also known is a stereoscopic camera called Bumblebee comprising two or three digital image sensors, communicating using a FireWire interface (IEEE-1394) and a GPIO (General-Purpose Input/Output) port, having a fixed image capture frequency and a fixed resolution. A first computer program is run on a microcomputer connected to the camera by the two connections, and makes it possible to control the camera, while a second computer program run on the microcomputer makes it possible to perform stereoscopic correlations to generate an image of the disparities. But since the resolution and the image capture frequency are fixed, it is not possible to use this camera dynamically and adaptively in an environment in which some objects are observed in rapid relative movement, and others in slow relative movement.
Also known is a stereoscopic camera called Duo3D, in which the image capture frequency is configurable by a programming interface command, related in predefined modes to resolutions in both dimensions of the image that are modified by binning. However, this camera is configured for the computerized perception of objects at a short distance, and is not suitable for observing an environment during movement.
There is therefore a need for a stereoscopic image capture system providing adaptive image capture in the face of relative movements of objects around the image capture device.